Iterative transcription factor screening enables rapid generation of microglia-like cells from human iPSC - TFiMGLs are responsive to disease-relevant stimuli

Differentiation of induced pluripotent stem cells (iPSCs) into specialized cell types is essential for uncovering cell-type specific molecular mechanisms and interrogating cellular function. Transcription factor (TF) screens have enabled efficient production of a few cell types; however, engineering cell types that require complex TF combinations remains challenging. Here, we report an iterative, high-throughput single-cell TF screening method that enables identification of TF combinations for specialized cell differentiation, which we validated by differentiating human microglia-like cells. We found that the expression of six TFs, SPI1, CEBPA, FLI1, MEF2C, CEBPB, and IRF8, is sufficient to differentiate human iPSC into cells with transcriptional and functional similarity to primary human microglia within 4 days.